#include <core.h>
#include <htl/decoupled.h>
#include "common.h"

using namespace ch::core;
using namespace ch::htl;

namespace aes {

// reference: https://en.wikipedia.org/wiki/Advanced_Encryption_Standard

const std::array<uint8_t, 256> rcon_table {
  0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a,
  0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39,
  0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a,
  0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8,
  0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef,
  0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc,
  0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b,
  0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3,
  0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94,
  0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20,
  0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35,
  0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f,
  0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04,
  0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63,
  0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd,
  0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb
};

const std::array<uint8_t, 256> sbox_table {
  0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
  0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
  0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
  0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
  0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
  0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
  0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
  0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
  0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
  0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
  0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
  0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
  0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
  0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
  0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
  0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16
};

template <unsigned Nk>
struct encrypt {
  static const unsigned Nr = Nk + 6;
  __io (
    __in (ch_bit<32 * Nk>) key,
    (ch_valid_in<ch_bit128>) in,
    (ch_valid_out<ch_bit128>) out
  );

  encrypt() : sbox_(sbox_table) {}

  void describe() {
    auto rkeys = key_expand(io.key);
    auto state = ch_delay(add_roundkey(io.in.data, rkeys[0]));

    for (unsigned i = 1; i < Nr; ++i) {
      auto s_box = get_subbytes(state.clone());
      auto s_row = shift_rows(s_box);
      auto s_col = mix_columns(s_row);
      state = ch_delay(add_roundkey(s_col, rkeys[i]));
    }

    auto s_box = get_subbytes(state);
    auto s_row = shift_rows(s_box);
    io.out.data  = ch_delay(add_roundkey(s_row, rkeys[Nr]));
    io.out.valid = ch_delay(io.in.valid.as_int(), Nr+1, false);
  }  

private:

  auto get_subword(const ch_bit32& in) {
    auto out0 = sbox_.read(ch_aslice<8>(in, 0));
    auto out1 = sbox_.read(ch_aslice<8>(in, 1));
    auto out2 = sbox_.read(ch_aslice<8>(in, 2));
    auto out3 = sbox_.read(ch_aslice<8>(in, 3));
    return ch_cat(out3, out2, out1, out0);
  }

  auto get_subbytes(const ch_bit128& state) {
    auto out0 = get_subword(ch_aslice<32>(state, 0));
    auto out1 = get_subword(ch_aslice<32>(state, 1));
    auto out2 = get_subword(ch_aslice<32>(state, 2));
    auto out3 = get_subword(ch_aslice<32>(state, 3));
    return ch_cat(out3, out2, out1, out0);
  }

  auto add_roundkey(const ch_bit128& state, const ch_bit128& key) {
    return state ^ key;
  }

  auto shift_rows(const ch_bit128& state) {
    return ch_shuffle<16>(state, {11, 6, 1, 12, 7, 2, 13, 8, 3, 14, 9, 4, 15, 10, 5, 0});
  }

  auto xtime(const ch_bit8& x) {
    auto m = ch_cat(0_b, 0_b, 0_b, x[7], x[7], 0_b, x[7], x[7]);
    return ch_cat(ch_slice<7>(x), 0_b) ^ m;
  }

  auto mix_row(const ch_bit8& x) {
    auto x2 = xtime(x);
    auto x3 = x2 ^ x;
    return ch_cat<ch_vec<ch_bit8, 4>>(x3, x, x, x2);
  }

  auto mix_columns(const ch_bit128& state) {
    ch_bit128 out;
    for (unsigned c = 0; c < 16; c += 4) {
      auto r0 = mix_row(ch_aslice<8>(state, c+0));
      auto r1 = mix_row(ch_aslice<8>(state, c+1));
      auto r2 = mix_row(ch_aslice<8>(state, c+2));
      auto r3 = mix_row(ch_aslice<8>(state, c+3));
      ch_asliceref<8>(out, c+0) = r0[0] ^ r1[3] ^ r2[2] ^ r3[1];
      ch_asliceref<8>(out, c+1) = r0[1] ^ r1[0] ^ r2[3] ^ r3[2];
      ch_asliceref<8>(out, c+2) = r0[2] ^ r1[1] ^ r2[0] ^ r3[3];
      ch_asliceref<8>(out, c+3) = r0[3] ^ r1[2] ^ r2[1] ^ r3[0];
    }
    return out;
  }

  auto rot_word(const ch_bit32& w) {
    return ch_shuffle<4>(w, {0, 3, 2, 1});
  }

  auto key_expand(const ch_bit<32 * Nk>& key) {
    static const unsigned Nr = Nk + 6;
    static const unsigned Nw = 4 * (Nr + 1);

    ch_bit32 rkeys[Nw];
    for (unsigned i = 0; i < Nk; ++i) {
      rkeys[i] = ch_aslice<32>(key, i);
    }

    for (unsigned i = Nk; i < Nw; ++i) {
      ch_bit32 temp;
      if (0 == i % Nk) {
        auto rot = rot_word(rkeys[i-1]);
        temp = get_subword(rot) ^ rcon_table[i/Nk];
      } else
      if (Nk > 6 && (4 == i % Nk)) {
        temp = get_subword(rkeys[i-1]);
      } else {
        temp = rkeys[i-1];
      }
      rkeys[i] = rkeys[i-Nk] ^ temp;
    }

    ch_vec<ch_bit128, Nr+1> out;
    for (unsigned i = 0; i <= Nr; ++i) {
      out[i] = ch_cat(rkeys[4*i+3], rkeys[4*i+2], rkeys[4*i+1], rkeys[4*i+0]);
    }

    return out;
  }

  ch_rom<ch_bit8, 256> sbox_;
};

}

static const auto KEY = 0x3c4fcf098815f7aba6d2ae2816157e2b_h;
static const auto PLAIN_TEXT = 0x340737e0a29831318d305a88a8f64332_h;
static const auto CIPHER_TEXT = 0x320b6a19978511dcfb09dc021d842539_h;

int main() {

  ch_device<aes::encrypt<4>> encrypt;
  ch_tracer tracer(encrypt);

  ch_tick ticks = 0;  
  ticks += tracer.run([&](ch_tick t)->bool {
    switch (t) {
    case 0:
      encrypt.io.key     = KEY;
      encrypt.io.in.data = PLAIN_TEXT;
      break;
    case 2:
      encrypt.io.in.valid = true;
      break;
    case 4:
      encrypt.io.in.valid = false;
      break;
    }
    return (!encrypt.io.out.valid && t < MAX_TICKS);
  }, 2);

  std::cout << "simulation ended after " << ticks << " ticks" << std::endl;
  std::cout << "encrypt.key      = " << encrypt.io.key << std::endl;
  std::cout << "encrypt.in.data  = " << encrypt.io.in.data << std::endl;
  std::cout << "encrypt.out.data = " << encrypt.io.out.data << std::endl;
  std::cout << "encrypt.out.valid = " << encrypt.io.out.valid << std::endl;

  CHECK(encrypt.io.out.valid);
  CHECK(encrypt.io.out.data == CIPHER_TEXT);

  ch_toVerilog("aes.v", encrypt);
  ch_toFIRRTL("aes.fir", encrypt);

  tracer.toText("aes.log");
  tracer.toVCD("aes.vcd");
  tracer.toVerilog("aes_tb.v", "aes.v");
  int ret = !system("iverilog aes_tb.v -o aes_tb.iv")
          & !system("! vvp aes_tb.iv | grep 'ERROR' || false");

  return (0 == ret);
}
